1. Field of the Invention
The present invention relates to a rod connector for supporting a bone connection rod which connects bones, for example, a breast bone, a lumbar vertebra or the like, and more particularly to a rod connector structured such that a connector main body supporting the rod freely swings with respect to a shank portion attached to an implant, for example, a screw or the like.
2. Description of the Related Art
As shown in FIG. 1, in a conventional bone connecting method, a plurality of screws (implants) 103 is screwed in to a lumbar vertebrae, and each screws 103 is supported by a rod 105 each other. And a conventional rod connector 107 interconnects the screws 103 and the rod 105.
As shown in FIG. 2, the conventional rod connector 107 is comprised of a connector main body 113 integrally formed in a distal end of a shank portion 109 supported by a head portion of the screw 103. The connector main body 113 is provided with a rod insertion hole 111 allowing to freely insert the rod 105 (shown in FIG. 1) and a locking screw 115 for pressure fixing the rod 105.
According to the structure mentioned above, even in the case that a position of the screw 103 is slightly displaced, it is possible to fine adjust the position of the rod connector 107 by adjusting a position of the shank portion 109 and a rotation of the shank portion 109 around an axis thereof with respect to the screw 103, whereby it is possible to properly support the rod 105. However, the rod connector 107 can be adjusted with respect to the screw 103 only in a range that the shank portion 109 can rotate. Accordingly, there is a problem that an adjustable range is small.
Further, according to Japanese Patent Application Laid-Open No. 11-318932, there is disclosed a structure in which a connection device corresponding to the rod connector 107 of the related art mentioned-above is constituted by a plastically deformable member, and a rod is properly supported by plastically deforming the connection device.
In this case, there is also a problem that a freedom of adjusting the rod connector with respect to the screw is small.